1. Field of the Invention
The present invention generally relates to a display device and a manufacture method thereof. Particularly, the present invention relates to a display device using quantum dot phosphor and a manufacture method thereof.
2. Description of the Prior Art
The Liquid Crystal Display (LCD) device is mainly composed of a liquid crystal panel and a backlight module. The liquid crystal does not illuminate, therefore it needs a backlight module to generate light, which is controlled by the molecules of the liquid crystal of the liquid crystal panel to produce images. For good color performance of the generated images, the collocation of the light generated by the backlight module and the color filter at the front side of the liquid crystal panel has become an important research topic.
The light sources extensively used in a backlight module in the industrial circle are mainly cold cathode fluorescent lamp (CCFL) and light emitting diode (LED). The phosphors generally used in CCFL are BAM:Eu2+, LaPO4:Ce, Tb, Y2O3:Eu3+, wherein the red light and the green light are a part of the linear spectrum. The spectrum has virtues of narrow full width at half maximum and high color saturation. However the phosphors cannot be excited by blue light and cannot be used in white LED using blue exciting light. Therefore, the light generated by CCFL has high color saturation, and color performance of CCFL is usually better than that of the general white LED. When LED is used as a light source, because conventional phosphor have a greater full width at half maximum (FWHM), the color saturation will be lower and the color of images often is not satisfying.
FIG. 1 shows an optical spectrum of a LED using conventional phosphors and a corresponding transmittance spectrum of a color filter. The optical spectrum generally includes a blue peak 11, a green peak 13, and a red peak 15; the transmittance spectrum of the color filter respectively has a blue peak of blue color resist portion 21, a green peak of green color resist portion 23, and a read peak of red color resist portion 25. As FIG. 1 shows, the blue peak 11, the green peak 13, the red peak 15 and their corresponding blue peak of blue color resist portion 21, green peak of green color resist portion 23, and read peak of red color resist portion 25 are somewhat mismatched, therefore the color purity is not good. Besides, the waveforms of green peak 13 and red peak 15 are wider and not distinct so that the green peak 13 and the red peak 15 respectively overlap with uncorresponding color resists. Therefore, a light corresponding to the green peak 13 may pass through the blue color resist or the red color resist, which further results in color impurity. Similarly, a light corresponding to the red peak 15 may also pass through the green color resist, affecting the light purity.